Compound



UNITED STATES Patented January 12, 1904.

PATENT OFFICE.

COMPOUND APPLICABLE FOR INSULATING MATERIAL OROTHER PURPOSES.

SPECIFICATION forming part of Letters Patent No. 749,224, dated January 12, 1904. Application filed April 25, 1902- Serial No. 104,711. (No specimens.)

To all whom, it may concern:

Be it known that I, LEONARD M. RANDOLPH, a citizen of the United States, residing in Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Compounds Applicable for Insulating Material or other Purposes, of which the following is a specification.

This invention relates, primarily, to compositions used in the arts to form a covering for electrical implements, such as wires, cables, and other conductors which under ordinary conditions of use require an insulating coating. Many such compositions have long been known and all contain as a basic ingredient some substance of a gummy nature which is generally combined with absorbents and binders of one sort or another to impart to the resulting compound solidity, strength, and durability. These various compounds are quite as good insulators as glass and rubber and, owing to their qualities of durability and comparative cheapness, have been largely employed in place of those older and better-known dielectrics. In three Letters Patent of the United States, numbered and dated, respectively, as follows: 698,856, April 29, 1902, 699,713, May 13, 1902, and 701,392, June 3, 1902, the applications for which were filed by me on September 5, 1901, several new compounds of this nature are described, and they all contain as a basal ingredient a substance known in the art as varnish residue and called in the trade varnish mud. This sub- ,stance is the waste product obtained from the cleaning of tanks used in the manufacture of varnishes, japans, and shellacs and has heretofore been of little use, and consequently valueless. Heretofore and previous to my inventions set forth in the above Letters Patent the various compounds of this nature have generally contained as abase gum-shellac, which has been used with or without copal varnish. To this base some absorbent has commonly been added to give solidity, and various fibrous substances, such as asbestos and mica, have been employed to impart tenacity and durability. The few compounds of this sort which have attained importance or success are not entirely inexpensive in their production, owing, probably, to the use of shellac and other gums in their composition, nor are they entirely free from such inherent defects and imperfections as insufficient insulating capacity, liability to deteriorate under the action of heat, cold, moisture, liability to disintegrate when subjected to shocks, jarring, and rough use.

In the three Letters Patent referred to above, wherein various compounds are described by me, it is set forth that varnish residue may be combined with certain other ingredients and a perfect insulating material produced, that such material is cheaper and better than any similar composition heretofore known, and that besides its value as an insulator it is capable of a large number of uses, especially as a substitute for rubber.

The object of the present inventionis to simplify the manufacture of such compounds.

In carrying out this invention varnish residue is employed as the base of the improved compound herein set forth. It is well known in the art to which this invention appertains that among the highest and best insulating substances or dielectrics vegetable oils and oxids are classed. Clear Calcutta oil, commonly known as linseed-oil, is a good example of vegetable oil which is commonly used as an insulating fluid. If this oil be boiled,it loses any water which may be mechanically held within it, and it is probable that it also loses certain indeterminate lighter oils of slight density. At any rate the boiled oil is found to be more dense than the original oil and of considerably greater insulating capacity. Varnish residue is the thickened mass left over after the boiling of a more or less complex mixture of vegetable oils and gums.

Chemically, it seems to consist of various ox- I ids partially dissolved in vegetable oils. Theoretically, therefore, it should be an excellent insulator, and, in fact, it is found that under a pressure of one hundred tons it has resisted an electromotive force of forty-seven thousand volts at three-eighths of an inch separation of the terminals.

In accordance with the present invention all the substances contained in the varnish residue which are in their natural state of a liquid density are as far as possible removed. These substances which are removed from the varnish residue comprise lighter oils, as naphtha and turpentine, various denser vegetable oils, and especially Calcutta oil, and certain viscous or semiliquid gums. The removal of these substances is effected by subjecting the varnish residue to a relatively moderate degree of heat in order to render the varnish residue of a comparatively thin consistency, and as soon as the point of thinnest consistency is reached the mass is strained through a suitable straining-cloth. The heat during this first stage of operations should be gradually applied and should not be raised above 200 Fahrenheit, and great care should be exercised during this stage lest the volatile gases from the naphtha, turpentine, and other of the lighter oils, which are continually escaping from the heated mass, take fire or explode. During the heating of the mass and owing to the presence of the vegetable oils all the solid particles in the mass are highly insulated. The straining, which may be effected as soon as the heat has rendered the mass comparatively thin, removes all of the liquid constituents of the mass which have not been previously volatilized. The residue which is obtained after the straining process is preferably reheated, and a high degree of heat may be employed in this stage, it being found practicable at present to employ a temperature of 4LOO to 500 Fahrenheit during this reheating, although a much less degree of heat may be employed and the residue subjected to a slow heating. The object of the reheating is to thoroughly dry and harden the mass. It is not absolutely necessay, however, to even reheat the residue which is left after the straining process, inasmuch as the drying and hardening may be accomplished by continued exposure of the residue to currents of air.

Instead of solidifying the varnish residue by removing the liquid substances, as above described, an absorbent substance may be employed to render solidity to the mass, and for this purpose it has been found useful to employ peat in varying proportions. The peat is preferably added to the varnish residue after the latter has been heated quite hot, and the resulting mass may then be molded or first allowed to cool and in the latter case may .be ground or broken up to be used at a later time. To this mixture of peat and varnish an insulating material.

the compound and impart durability to the same; but a good workable compound is obtained if the fibrous material alone'be mixed with the varnish residue and the peat altogether omitted from the composition.

When powdered peat is added to the varnish residue to absorb the oily constituents of the same, the proportions of the peat and Varnish residue employed will largely depend upon the density of the varnish residue. As it is ordinarily obtained satisfactory results have been reached by using from one to four parts of peat to four parts of Varnish residue. In the mixture of varnish residue and a binding substance the proportions of varnish residue and binder are capable of the widest variations, the nature of the binder, as well as the strength of the resulting compound, determining the proportions.

To mold the compound, it is heated hot and placed in suitable dies, which may also be heated. Pressure is then applied to the dies and maintained from five to fifteen minutes. The material thereafter and while remaining in the dies is allowedv to set and become cold and is then removed from the dies and is ready or prepared for the market. If it is desired, a coloring-matter may be added to the compound while hot to impart to it a particular shade. When cold, the material may be turned, and the surface may be rendered very smooth and highly polished. Owing to the similarity in the properties of this compound to those of or containing rubber, guttapercha, and similar gums, said compound is useful for various purposes besides its use as It may be employed, for instance, extensively in plumbing for washers and packings, and it is equally useful to form packings for valves and moving parts of machinery. It may also be employed for making golf-balls and numerous other articles and devices of manufacture and commerce, and accordingly it is understood that.

its use is not limited to such purposes alone for which its insulating capacity makes it valuable.

I claim as my invention 1. The herein-described compound which comprises varnish residue altered as set forth by the action of heat, substantially as described.

2. The herein-described compound which comprises varnish residue deprived of its liquid constituents.

3. The herein described compound which comprises varnish residue altered by being deprived of its liquid constituents, and hardened and toughened by the action of heat, substantially as described.

4. The herein described compound which comprises a mixture of varnish residue and comprises a mixture of varnish residue and a IO an absorbent, substantially as described. fibrous material, substantially as described.

5. The herein described compound which This specification signed and witnessed this comprises a mixture of varnish residue and 18th day of April, A. D. 1902. 5 peat, substantially as described.

6. The herein-described compound which LEONARD RANDOLPH comprises a mixture of varnish residue and a In presence of binder, substantially as described. ANTHONY N. J ESBERA,

7.. The herein-described compound which LUorUs E. VARNEY. 

